1. Field of the Invention
The present invention relates to a hammer driven soil coring device for use on golf course greens.
2. Description of Prior Art
Generally devices used to extract a soil plug from golf course greens are adequate in their operation, however, they lack versatility, accuracy and consistency that is necessary to achieve the best result. Several devices used to extract a soil plug from golf course greens exist, generally exhibiting the same inconsistencies. For example, when a soil plug is extracted with a hole cutter that utilizes a two piece cutting cylinder, each side or section of the cutting cylinder is driven with a mallet. Such a cutter is commonly used to avoid damaging the hole, as can happen when a manually rotated type hole cutter is used, or when it is desired to extract a soil plug out of the green in one piece. A one piece soil plug can also be extracted by using a rotating type cup hole cutter, but often it is extremely difficult to manually drive the hole cutter to the desired depth. So often a mallet driven two piece cylinder type hole cutter is utilized because it is generally less laborious to drive this type of hole cutter than the manually rotated type. There are several inherent problems with the mallet driven two piece cutting cylinder hole cutters because the cutting cylinder is in two sections. There is a tendency for the gap between the two sections to snag grass blades when the device is rotated to separate the soil plug from the soil at the base of the hole. Also when this type of hole cutter is extracted from the hole, there is a tendency for the soil trapped between the two cutting cylinder sections to fall out because there is a slight increase in the diameter of the cutting cylinder because the tension placed on the sides of the cylinders is negated when the device is removed from the hole. Another problem with the two piece cutting cylinder mallet driven hole cutter is that the cutting sections are held in place with a cage like device that has a series of flat circular rings supported with welded bracing between each of the rings. The problem is that, in operation, the device is placed where the hole is to be cut, a ring rests on the surface of the green which can, if the green surface is moist, cause the ring to depress the area of the green it is in contact with. This leaves an indentation around the top of the hole which is not a desirable condition. Also, since it is required to cut the hole vertically. Placing this device on a slope or incline makes it impossible to cut a vertical hole, since the ring that contacts the green surface must lay with the entire circumference of the ring contacting the green surface, if it were placed on a slope of any degree the hole would not be able to cut vertically. Often, even though a consistent depth may be achieved when cutting the hole, due to different soil condition, moisture content and grass variety, when the soil plug is placed in the old hole the plug may be above or below the grade of the green. The two piece cutting cylinder hammer driven hole cutting device cannot be used to extract a plug by manually rotating the device. This causes a problem when there is a need to remove a portion of the soil plug when the plug is above or below the grade of the green. Another difficulty with the aforementioned device is that, in operation, the operator must crouch to drive the cutting cylinders and drive each section of the cutting cylinder separately. The depth gauge devices used on these devices are not consistent. A strip of tape is often used to indicate the depth the cutter is at, or a series of screws that screw through a series of nuts that are welded to the top ring of the housing. The operator must again crouch to see if the cutting cylinders are at the desired depth, the tape does not stop himm, so often the hole is cut too deep or too shallow. The screw type depth gauge stops the cutting cylinders at the desired depth but are generally ineffective because they are not strong enough to sustain the continuous hammering resulting in bending or breaking of the screws. Also the aforementioned devices have no means of tamping the soil plug so that it is on a grade that is level with the surface of the green.